Stripping larger than #10 Wire

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So I have always been taught to strip larger wires like a pencil, not ring the wires so I don't damage the integrity of the conductor. I always assumed this was a code thing, until I tried to explain to a apprentice , I'm not a fan of the because I told you mentality.
But I can't find it in the code, so is it just a best practice or a code thing I can't find? Any help would be appreciated.
 

Carultch

Senior Member
Location
Massachusetts
So I have always been taught to strip larger wires like a pencil, not ring the wires so I don't damage the integrity of the conductor. I always assumed this was a code thing, until I tried to explain to a apprentice , I'm not a fan of the because I told you mentality.
But I can't find it in the code, so is it just a best practice or a code thing I can't find? Any help would be appreciated.

I'm not sure if it is an NEC thing or not, but the reason you want to avoid scratching the wire is its mechanical integrity.

When you cut through a strand of wire, it is no longer as strong as it once was. The cut part of the strand is a stress point, subject to mechanical failure. After years of the many expansion/contraction cycles, that strand can bend and break in the termination. And then your wire no longer has as much material in contact with the termination for carrying current.

Have your apprentice practice with a few scrap pieces of wire, and demonstrate that the cut strands can break in the lugs and ring terminals.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
So I have always been taught to strip larger wires like a pencil, not ring the wires so I don't damage the integrity of the conductor. I always assumed this was a code thing, until I tried to explain to a apprentice , I'm not a fan of the because I told you mentality.
But I can't find it in the code, so is it just a best practice or a code thing I can't find? Any help would be appreciated.
I have never done it that way.

I carefully score a ring around the insulation and then split down the middle longways. It's easier with THHN. For XHH or URD I sometimes have to grab the split with my needlenose and peal.
 

Strathead

Senior Member
Location
Ocala, Florida, USA
Occupation
Electrician/Estimator/Project Manager/Superintendent
So I have always been taught to strip larger wires like a pencil, not ring the wires so I don't damage the integrity of the conductor. I always assumed this was a code thing, until I tried to explain to a apprentice , I'm not a fan of the because I told you mentality.
But I can't find it in the code, so is it just a best practice or a code thing I can't find? Any help would be appreciated.


It is a preference thing. I have done it both ways, but you can damage the integrity either way if you aren't careful. One could argue that carelessly ringing the cut is worse, but being a type A personality, I hate the look of a wire that has been stripped like a pencil.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
There are tools available that are specifically designed to strip the insulation without damage to the conductor strands.

Please don't talk too much about this issue in an open forum....we will end up having a code rule that requires the use of specific tools to strip the wire:)
 

PetrosA

Senior Member
Shh! That is a frightening thought.

Yeah, but maybe not such a bad one for the smaller gauge wires.

Many, many splices and devices I take apart (14-12 AWG) show signs of serious nicking from having been stripped with dykes or linesman pliers, and it usually doesn't take much to snap the wire off at that point. I've never seen large size cables snap apart regardless of whether they were stripped by scoring or whittling, possibly because in resi work our wires tend to be dramatically oversized and understressed, so the heat expansion/shrinkage is less of a problem than in commercial or industrial conditions where it's more likely that wires are sized much more closely to the actual load they'll be serving.
 

Smart $

Esteemed Member
Location
Ohio
There is no Code requirement on how to strip of insulation.

Pencil vs ring stripping advantages are myths, especially for low voltage wire. There is some credence in days of old for pencil stripping medium voltage insulation, but practically everyone uses molded stress cones nowadays... and all the ones I've used require a square trim of the insulation.

The main concern has been mentioned: nicking the wire can lead to mechanical stress fractures. The best practice is to score the insulation without the blade touching the conductor and use sheer force to separate the remaining web.
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
There are tools available that are specifically designed to strip the insulation without damage to the conductor strands.

Please don't talk too much about this issue in an open forum....we will end up having a code rule that requires the use of specific tools to strip the wire:)
hmmm....thats a thought....I will get right on that.
 

Carultch

Senior Member
Location
Massachusetts
Please don't talk too much about this issue in an open forum....we will end up having a code rule that requires the use of specific tools to strip the wire:)


How will the inspector ever be able to enforce that?
As long as wire insulation is removed without damage to the metal, how would an inspector know?
 

Hacks

Member
Location
NJ
How will the inspector ever be able to enforce that?
As long as wire insulation is removed without damage to the metal, how would an inspector know?
There's a lot of code requirements like that.

For example, how will an inspector know if you fully completed a raceway before installing the wire?
 
Thank you

Thank you

For all replies and input, I have learned something once again. Happens more and more, even though I've got more than 17 years in the trade. It's a good thing. ????
 

kwired

Electron manager
Location
NE Nebraska
There are tools available that are specifically designed to strip the insulation without damage to the conductor strands.

Please don't talk too much about this issue in an open forum....we will end up having a code rule that requires the use of specific tools to strip the wire:)
They didn't listen to what we had to say when we didn't like AFCI's...

How many tool manufacturer reps are on the code making panels or closely related somehow? That may be the main key here.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Well, I will say one thing, there are strippers available for sizes larger than #10. My regular pair are good for #12 - #6. You often can't find larger than #10 at a hardware store or big box, but look at an electrical supplier or online.
 

Smart $

Esteemed Member
Location
Ohio
If you read the manufacturers instructions they say not to ring the wires. While it's not in the NEC, the NEC says to follow the manufacturers instructions.
Can you please provide something to back that up: scan, link, etc.

FWIW, common strippers 'ring' the wires.

PS: WELCOME :thumbsup:
 
http://www.ilsco.com/e2wViewStaticPageContent.aspx?PageURL=Reference&parentId=2100001003

The page that covers cpm adapters has the least amount of required reading.

Yes, common strippers leave a small mark on the conductors. Really, everything in the world comes down to common sense. I can put five guys on wire termination and all five will ring it at a different depth. Even better, that depth can change based on how sharp the blade is or how many wires they've stripped that day (fatigue). I'm sure they're are super guys out there, but I doubt any of them could squeeze a pair of strippers to the point of not getting the same, repeatable results the manufacturer intended.
 
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